Synthesis, Characterization, and Electro-Optical Properties of ZnII Complexes with pi-Conjugated Terpyridine Ligands
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Winter, Andreas; Friebe, Christian; Chiper, Manuela; Schubert, Ulrich S.; Presselt, Martin; Dietzek, Benjamin; Schmitt, Michael; J\", ; urgen Popp,
- Abstract:
- A series of nine zinc(II) complexes containing substituted 4’-
phenyl-2,2’:6’,2’’-terpyridines as ligands is synthesized and fully
characterized. The ground-state structures of four examples
are calculated by means of DFT and their structural features
are confirmed by experimental Raman spectroscopy. Special
focus is placed on the degree of p-electron delocalization between
the terpyridine unit and the attached phenyl moiety.
Applying Bader’s quantum theory of atoms in molecules
(QTAIM) and visualizing the electron-density distribution by intermolecular
D1 plots reveals an increase in ellipticity—and
therefore p-electron delocalization—for phenylvinyl-substituted
derivatives compared to phenylethynyl-substituted ones. Experimentally, this is verified by spectroscopic means, because
an increase in ellipticity goes along with a pronounced decrease
of the HOMO–LUMO energy band gap. Overall, the lateral
p-conjugated substituents are found to strongly influence
the electro-optical properties of the complexes. In solution, the
color of emission can be modulated from violet to cyan (425–
487 nm) and high quantum yields (FPL up to 0.60) are observed.
Thin solid films of the complexes in a matrix of poly(-
methyl methacrylate) have been inkjet-printed, and their photophysical
behavior (bright emission, FPL up to 0.30) reveals
their potential as new emissive materials for applications in
light-emitting devices.
- Year:
- 2009
- Type of Publication:
- Article
- Journal:
- Chemical Physics and Physical Chemistry
- Volume:
- 10
- Pages:
- 787 - 798